Ulipristal acetate [17alpha-acetoxy-11beta-(4-N,N-dimethylaminophenyl)-19-norpregna-4,9-diene-3,20-dione; hereinafter, may be referred to as UPA], which is a steroid compound possessing antiprogestational activity and antiglucocorticoidal activity, is on the market as an emergency contraceptive drug in the United States and Europe.
As a crystalline ulipristal acetate, for example, Japan Patent No. 2953725 publication (JP-2953725B, PTL 1) discloses a crystalline UPA having a melting point at a temperature of 118 to 121° C. obtained by recrystallization from a mixed solvent of methanol and water. WO96/30390 publication (PTL 2) discloses a crystalline UPA having a melting point at a temperature of 183 to 185° C. obtained by crystallization from diethyl ether. Japanese Patent Application Laid-Open Publication No. 2006-519255 (JP-2006-519255A, PTL 3) discloses a crystalline UPA having a melting point at a temperature of 183 to 185° C. obtained by recrystallization from an ethanol aqueous solution (90%). Japanese Patent Application Laid-Open Publication No. 2006-515869 (JP-2006-515869A, PTL 4) discloses a crystalline UPA having a melting point of 189° C. obtained by recrystallization from an ethanol/water (80/20) mixed solvent. Japanese Patent Application Laid-Open Publication No. 2009-539964 (JP-2009-539964A, PTL 5) discloses a crystalline UPA having a melting point at a temperature of 184 to 186° C. obtained by recrystallization from a mixed solvent of ethanol (230 mL) and water (260 mL).
There is still a need for new crystalline forms of ulipristal acetate having improved solubility and/or improved bioavailability.